007bd18bcb
This PR adds extensibility to the `evalAndSuggest` procedure used to implement `try?`. Users can now implement their own handlers for any tactic. The new test demonstrates how this feature works.
31 lines
907 B
Text
31 lines
907 B
Text
import Lean
|
|
|
|
open Lean Meta Elab Tactic Try
|
|
|
|
-- Install a `TryTactic` handler for `assumption`
|
|
@[try_tactic assumption]
|
|
def evalTryApply : TryTactic := fun tac => do
|
|
-- We just use the default implementation, but return a different tactic.
|
|
evalAssumption tac
|
|
`(tactic| (trace "worked"; assumption))
|
|
|
|
/-- info: Try this: · trace "worked"; assumption -/
|
|
#guard_msgs (info) in
|
|
example (h : False) : False := by
|
|
try? (max := 1) -- at most one solution
|
|
|
|
-- `try?` uses `evalAndSuggest` the attribute `[try_tactic]` is used to extend `evalAndSuggest`.
|
|
-- Let's define our own `try?` that uses `evalAndSuggest`
|
|
elab stx:"my_try?" : tactic => do
|
|
-- Things to try
|
|
let toTry ← `(tactic| attempt_all | assumption | apply True | rfl)
|
|
evalAndSuggest stx toTry
|
|
|
|
/--
|
|
info: Try these:
|
|
• · trace "worked"; assumption
|
|
• rfl
|
|
-/
|
|
#guard_msgs (info) in
|
|
example (a : Nat) (h : a = a) : a = a := by
|
|
my_try?
|